The wavelength of a RF/Microwave signal can be measured using a reaction cavity, which can be tunable and connected to a shunt, such as explained in “Technique of Microwave Measurements, volume 11 of MIT Radiation Laboratory Series. McGraw-Hill, New York, 1947, Chapter 5”.
US 20070161263 RESONANT FREQUENCY FILTERED ARRAYS FOR DISCRETE ADDRESSING OF A MATRIX uses a substrate and intersecting frequency filtered arrays. A material is located between such arrays and changes a property in response the stimulus received simultaneously from both arrays. A resonance is between the two arrays.
U.S. Pat. No. 7,133,180 RESONANT IMPEDANCE MATCHING IN MICROWAVE AND RF DEVICE discusses devices and techniques for using microwave or RF resonators to provide DC bias, DC blocking, and impedance matching to microwave or RF devices.
U.S. Pat. No. 9,362,604 RF PLANAR FILTER HAVING RESONATOR SEGMENTS CONNECTED BY ADJUSTABLE ELECTRICAL LINKS defines an adjustable radio frequency filter in planar technology.
EP 3 113 281 COUPLING ELEMENT AND CAVITY RESONATOR DEVICE WITH A COUPLING ELEMENT relates to coupling two adjacent cavity resonators.
WO2012153529 ELECTROMAGNETIC RESONANCE COUPLER provides an electromagnetic resonance coupler that contactlessly transmits a high-frequency signal between two resonance wirings.
U.S. Pat. No. 7,274,262 METHODS AND APPARATUS BASED ON COPLANAR STRIP LINES relates to a standing wave oscillator to generate at least one voltage standing wave, comprising a closed-loop coplanar strip line including two conductors, and at least one amplifier disposed between the two conductors at a first location.
GB 1529941 mentions using a transducer to drive coupled resonators to form a surface wave filter.
U.S. Pat. No. 9,536,758 TIME VARYING FREQUENCY POWERED SEMICONDUCTOR SUBSTRATE HEAT SOURCE, US 2019-0109024 TIME VARYING FREQUENCY POWERED HEAT SOURCE, each of which is incorporated herein by reference in its entirety, relate to selecting a frequency of an applied input signal to select a location along a length of variable spacing between two or more individual electrodes to generate heat and control temperature gradient in an adjacent substrate.